Solid error led lit with arduino Uno and pump question.

General discussion of using Roboclaw motor controllers
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azabel
Posts: 3
Joined: Thu Jul 07, 2016 10:33 am
Solid error led lit with arduino Uno and pump question.

Post by azabel »

Hi all!

I've bought a roboclaw 2x15A. I connected it to arduino mega via de 14 and 15 pins with no loads. Tried to set the packet serial mode and use my sketch. I noticed the buttons MODE and LIPO appear to be exchanged their functions. Can i reset the roboclaw via usb? The board is powered via a 12v regulated 2 amp power supply. On his final location it will be powered via a 12 v solar charge controller.

What settings can be used to mitigate the regenerative function and dont damage the controller?

The pump question is: Can i use the roboclaw to reduce the current peak at the start of a shurflo 2088 12v diaphragm pump?
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Basicmicro Support
Posts: 1594
Joined: Thu Feb 26, 2015 9:45 pm
Re: Solid error led lit with arduino Uno and pump question.

Post by Basicmicro Support »

You can use the Ion Motion software with a USB connection to swap the LIPO and MODE buttons back.

You will need to do one of the following depending on the amount of regen and how the motors need to operate.

1. To prevent regen down slow down the motors quickly. If they slow down at their natural rate(eg due to friction/load) they will produce no regen.
2. You can set the Roboclaw max main voltage limit to about 2v above teh 12v supply voltage. Then if regen does happens and the main voltage rises above that set point the Roboclaw will brake the motor(by shorting the motor leads together). This will stop the motors quickly but will also prevent regen from increase the voltage high enough to damage the roboclaw or the power supply.
3. You can add a 12v battery in parrallel which will handle the regen energy
4. You can add an active voltage clamp circuit. If you are interested in this option email support@ionmc.com and we'll walk you through the options.

For the pump start current question: As long as the physical stiction does not prevent the pump from turning you can limit the current for the start to whatever you need it to be.

One thing to note, when you are using PWM to drive the motor the current to the motor can be higher than the current from the power supply(unless you are at 100% duty then it is equal to it). This is because PWM is changing the average voltage reaching the motor but the total power coming form the power supply still remains the same to the motor(minus a very small amount due to loses).

For example if you are PWMing the motor at 10% duty and pulling 20amps(at an average of 1.2v), the power supply is actually only providing 2amps(at 12v).

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